Flexible screen support



June 19, 1945. BURLSv FLEXIBLE SCREEN SUPPORT Filed April 5, 1943' 3 Sheets-Sheet 2 J. P. BURLS FLEXIBLE SCREEN SUPPORT June 19, 1945.

Filed April 5, 1943 Sheets-Sheet 3 7 a 4 m HMHHNI I I IA/I IMHH I H l HH l Hmu| 4 w W ND ml l HI HI I I INHH I IHHH Hum! H 4 M m 2).

each roflthe'. member-sl-iand i.

tending member, generallylindicated .as It, which Patented June 19, 1945 miexmn s scnnsn sueron'r" John P.=,-Bur1s, London W. 1,ulilnglanfl assignorv to Nordberg- Manufacturing Company, 1 Wis.,.a conpcration of Wisconsin Milwaukee, r

mesh or separating n emheriof ascr'een.

Ano'ther purpose --is the *provision "ofian improved screen'and *s'creen'support in which an --inilated memberis'employedto'supportthemesh fDIflSC pEi'Zting element.'

* i employ .any {sui-table't m'eans 'forwinflatin-g' and deflatingthe space -9. '1. illustrate for "example any==suitable valveelement 1 0, 'the:details {of I other purpose" is" th'eprovisionof a'support in which aninfiatedmember 'of "flexible material is employed, with means for controllin a "and; if necessary; varying'the' inflation.

Other-purposes will "appear fro m"timej to time "in the course of-the specification and claims.

Theinvention "is illustrated more or'i'1ess: -dia "grammatically in the accompanying drawings,

wherein?" Figure l'iis a planviewj of the screenlenibodying the invention," with parts"broken. away,;anfd parts in section;

Figure 2 is "a 'Fieure'i; .c "Figure "3 is a section; on an-ienlaitged 'scale on theline3-3 of Figure 1; -i

. Figure 51 is a section similarito figural-illusse ction 2 along 1 the 2-242 of tratin gga'varlanfl'form ofjtheinvention; L I

' with rpa'rtsglin "-Figure f5jis" aiip'artialp lan' view, section; of a screen frame illustrating ;a variant iapplicationidftheinventiomvand 'plic a'tionofthe invention. V 1

j Like ,parts' are indicated iby like characters throughout the specification. an'df.drawin'gs.

ent invention. 'I'may forexample use 'an ofdi-.

nary valve of the Schraeder type, a one-way-valve, which meadily admits liquid 1 or ga's underpressure, ?but*whiehk is mummy-sealed shut by pressure within' the 'space' 9,- proi'r-ide'd 'by 'th distens'ion aiid the corresponding compressive efi-ectof "the relativelythinflexible" upperand" side WallSDf theimenlb'er 8. The end's of the elements above "described may" be "closed in 'any suitable} fashion so that the only access to the interior-space -9 is throughthevalve-lfl."

"iLdnaypro'vi'de'any suitable meansior' tensionin'g the mesh l -deck hereinshowrifthe' entils of the nieshare dropped; into 'the upwardboneavities of the transversely-extending 'angle members "'I I, F2, flocated at and extending across the opposite ends of 'the deck.- ln order to tension the 'deck l provide transversely extendingangle 'members [3, 14, when may---be I drawn *downward into a locking relationship with' the angles Hand [2. The re- J "sult is an endwis'e tensiening ofthe'mesh I over :Tneueekmay a supp rt d in any suitable *manner upon anysuitable base. I illustrate fo'r Refe-jrr ng t me drawings,l generally'in'dicates a" screen mesh orffa'bri'c, which is. to begsupp'orted.

"It will'ibe understoodthat this meshimay' be sup ported upon a wide variety. of screen decks and sc'reensgan'd lithe detailsitheredf no notof Lthemselves formpart of "the presentf invention, For

convenience and ,to l ive a, practical application including .ls'ideiframe elements "2 ,liand .a pluralityofftransversely extendingmembers, eachoflwhieh isshown asinclu'ding ian anlels andanadjacent piece 4, theupp'erLe'nd of which,.-.as1.at\'5,.is parallel with the upper poiitionofl thelvertical or generally vertical'Yfiange .iof the viar' igrle. :"Looateii lbetween is a transversely ex- ,may be .of, rubber or .thellike .Itincludesia-portion'! .extending between the members 3 .and ;5

and. an upper,portionl8lhavingfaihollowL9,. Itwill ,be understood that, .whenithefihollow li is inflated with .anylsuitahle gastor/liquid, .the partsv may-be inithe positionfin which theypareshown-in :E-ieare "3, wane portion of the member 8 extending out above thei upper edges of the members 3 and member 8 providing a Ef'the upper walls of the somewhat yielding support for the screen-cloth or mesh 1.

"40 "ofthe' invention, therei's"illu'stratedascreen deek "the 'feed end of the screen, and one'or example a 'flexible, compression member 20 for more-coil spii-rigs' 'fl "'fo r:-the*di-scharge end of thefsoreen. Any suitable vibrating means may such as the motor 22 and'the unbalanced vibrating -'-'member '23. However, it willfbeunderstood thatahy suitable means may be employed for supporting and ior imparting-vibration to the deck.

.In"-the"formof Figure 4, inthe'place of-thepar- "tlcular fie'xible screen 'sup-portshown inFigure '3,

I' iIlustiate a variant'form. Referring to Figure 54,;ithet-h1esh 11 is supported directly upon a flexible tubular supporting member- 3B, zwhichmay I :be zinflated'tthrough the valve structure 3| and which, of course, has closed ends. It may be :housed between: thezvertical flanges 32; '33, preferably:.extendingiabove'theicenternf. the member v30. whezva-lveelements 3l'-:may-,-,extencl through apertures orrnotches inconejofithe -rmembers 32,233;

=I-twill Joe understood thatp-as to'both iorms, .the flexible element is'so;proportioned;as .to:be ,preferablyreadily -sremovab1ex from the relatively rigid 'surroundingsupportingelements; v

. Whereas theindividualelementszhave been illustrated as provided with separate valves whereby they may be individually inflated or deflated, it will be understood that, if desired, the entire be employed,

group may be interconnected to form part of a single system whereby the application of pressure at one point will serve to inflate all of the flexible supports The intercommunication may, for example, be provided by'tubing extending along one or both edges of the deck, preferably at such a level as to be out of contact with the mesh, or the tubing may be located on the exterior of the side frame members 2.

' I illustrate in Figure a variation of the invention in Which a plurality of the inflatable supports, illustrated as 50, have end passages 5| extendin outwardly through the side frame members 2 of the screen deck. These individual connections 5| are illustrated as connected by longitudinally extending passages 52, which may for convenience be located on the outside of the side frame member 2, and serve to associate a plurality of inflatable transversely extending members 50 into a single pneumatic or pressure system. 53 is an admission or discharge passage, which is effective for the entire system, and which may be provided with any suitable valve means not herein shown in detail. It will be understood that the Schraeder valve, if desired, may be employed, or any other suitable means for normally preventing escape of any liquid or gas, such as air, which may be supplied to the system.

It will be understood that the transversely extending passages 52 may be otherwise located, for

example just inside of the side frame element 2. The showing may be taken as broadly illustrative or diagrammatic, as the individual members may be connected by any suitable system of interconnecting passages.

In Figure 6, I illustrate the transversely extending members 50 as provided with individual valve tube passages 54, herein shown as extending outwardly through the side frame member 2.

It will be understood, of course, that in the form of Figures 5 and 6, any suitable type of flexible walled member may be employed, and the form of Figures 3 and 4 are merely illustrative of a practical solution of the problem.

It will be understood that any suitable fluid may be employed, air being satisfactory as a gas, and water as a liquid. However, any suitable fluid or mixture of fluids may be employed, provided, of course, that fluids which tend to damage the particular flexible substance employed are not used.

It will be realized that, whereas I have described and illustrated a p a t al and op rati device, nevertheless many changes may be made in the size, shape, number and disposition of parts without departing from the spirit of my invention. I therefore wish my description and drawings to be taken as in a broad sense illustrative or diagrammatic, rather than as limiting me to my precise showing.

The use and operation of the invention are as follows:

In supporting and tensioning a screen element on a screen frame, it is important to prevent sagging or distortion of the screen element and to keep it in a state of tension. It is, of course, possible to subject a screen element mechanically to transverse or longitudinal tension. Where the screen is tensioned over rigid supporting elements, there is always substantial wear.

According to the present invention, the screen-- ing element is supported by inflatable and preferably pneumatic members, which assist in keeping the screening element in proper tension and position. Any suitable screen deck may be employed, preferably including a square or rectangular frame, which may be mounted resiliently or vibratably upon any suitable base. It will be undertsood that in the use of the device, any suitable means may be employed for imparting vibration to the deck and thus to the screening element supported on the deck. The deck is provided with a plurality of transversely extending relatively rigid screening supports. These screening supports in turn have associated therewith the individual flexible inflatable supports above described. These flexible supports may, if desired, be secured to the rigid supports, or they may be held normally in flxed relationship thereto by the tension of the screening element itself. The result is a flexible supporting connection between the screening element, which reduces wear and assists in maintaining the screening element in proper position and tension. It will be understood that any suitable means maybe employed for clamping the longitudinal edges of the screen element in place.

In the employment of the invention, preferably the screening element is first positioned, as shown for example in Figures 1 and 2, and thereafter the pneumatic tubes of Figures 3 and 4 are inflated, thus providing ready means for subjectingthe screen cloth to any desired tension within suitable limits. Tension may be varied by varying the inflation of the pneumatic tubes or flexible screen supports.

The whole area of the screening element is tensioned evenly, with an increase in screening efllciency and the prolongation of the life of the screening element.

I claim:

1. In combination, in a screen, a screen deck having a plurality of transversely extending supports, means for tensioning a screen cloth across said supports, and additional means for tensionr ing said screen cloth, including flexible walled pneumatic elements, on said supports, in direct contact with the lower side of the screen cloth, and means for inflating said pneumatic elements. 2. In combination, in a screen, a screen deck having a plurality of transversely extending supports, means for tensioning a screen cloth across said supports, and additional means for tensioning said screen cloth, including flexible walled pneumatic elements, on said supports, in direct contact with the lower side of the screen cloth, means for inflating said pneumatic elements, and ducts extending between said elements, adapted to connect them in a single pneumatic system, whereby the pneumatic elements may be simultaneously inflated to a uniform pressure.

3. In combination, in a screen, a screen deck having a plurality of transversely extending supports, means for tensioning a screen cloth across said supports, and additional mean for tensioning said screen cloth, including flexible walled pneumatic elements, on said supports, in direct contact with the lower side of the screen cloth, and means for inflating said pneumatic elements, said supports constraining said screen cloth to an upwardly concave contour, taking the screen cloth in vertical section fromend to end of the screen.-

JOHN P. BURLS. 

